Local Teacher Challenges Our National 'Why' Expert

WHY THINGS ARE

Our explanation of why there are two high tides a day rather than one was not an unqualified success. Everyone hated it.

Physics teacher Sean R. of Orlando, for example, noted, ''Just because someone is a journalist doesn't qualify them (sic) to explain physical, medical, legal, chemical, economic and political phenomena.''

Sean is correct. We aren't ''qualified'' to explain anything. But we are forced to plunge ahead, giving it our best shot, because ''experts'' are the worst explainers of all, almost invariably incomprehensible, humorless and, as often as not, just as wrong.

To see what the column would be like in expert hands, let's turn it over to Sean the physics teacher, who has included a few sentences under the heading ''How I would have explained it.''

''On the side of the planet closest to the moon, the moon's gravity pulls the water up, hence one of the high tides. The moon is normally opposite the sun, so the usual effect is that the moon pulls on one side of the planet and the sun pulls on the other causing two bulges. This is not always the case though, so the tides are really a much more complicated phenomenon.''

A dazzling effort! One picky objection: If the moon were, in fact, ''normally opposite the sun,'' it would ''normally'' be a full moon, which it is not; hence the answer is preposterous.

But maybe there is always a full moon in Orlando. Some kind of Disney gimmick.

N.B. of Grosse Pointe, Mich., asks, ''Why, in recent decades, has there been a shortage of decent, eligible men for all the women around?''

Dear N.B.: There are always slightly more women around than men, since men aren't as healthy, get killed more often and are more likely to be in jail or prison. But the real answer to your question is: Women are choosier. They have a greater investment of time and energy in their offspring and thus are more careful about their mates. The benefit is that women, on average, are more perceptive than men. The down side is that women also notice how repellent most men are.

We hate writing about yawning because the mere mention of it causes people to yawn, and . . . excuse us . . . yurraahhhhya! . . . as we were saying, it causes people to yawn, and that hurts the reputation of the column. So: Robert Provine, a University of Maryland psychologist, says that all sorts of things happen when you yawn, including the contraction of the muscles in your inner ear. This causes the eardrum to tighten up, becoming less sensitive to pressure, i.e., sound.

By the way, we still get lots of mail asking why yawns are contagious, a question we answered eons ago and which we will hereby summarize: It's not caused by a germ. It's purely psychological, triggered by a ''yawn detector'' in the brain, and is probably an evolutionary adaptation that helps us, as social creatures, synchronize our wake-sleep pattern and keep our social group on the same wavelength.